FLUOROMETRIC MEASUREMENT OF IGG ANTIBODY-RESPONSES IN CATTLE VACCINATED WITH TRITRICHOMONAS-FETUS

A photometrically-measured indirect fluorescent antibody (IFA) test wa s developed to measure antibody levels in three heifers vaccinated int ramuscularly with two injections (two-week interval) of a vaccine cont aining formalin-killed Tritrichomonas foetus in oil adjuvant; a separa te animal served as a nonvaccinated control. Sera were collected weekl y and tested for specific IgG against T. foetus. Antibodies were detec table within two weeks of the initial injection and reached reciprocal titers as high as 7700 as estimated from previously tested reference sera. Titers peaked at six to eight weeks and remained at relatively h igh levels for the eleven-week study period. The fluorometric assay wa s easily developed and economical to perform; in addition, it more acc urately estimated IgG levels than standard slide IFA tests.